Optimally shaped bus connector

TECHNICAL FIELD

p-0002The present disclosure relates generally to power distribution devices and systems, and more particularly to bus connectors for connecting circuit breakers to power bus bars.

BACKGROUND

p-0003Circuit breakers are most commonly used to protect electrical equipment from overload and short circuit events. Large circuit breakers that carry thousands of amps of current are oftentimes installed into metal-enclosed switchgear assemblies, which are also referred to as “switchboards.” Switchgears have large electrical conductors called bus bars (or “buss bars”) that carry current from a power source, such as a power utility, through the circuit breakers, to loads that are protected by the circuit breaker. These large circuit breakers, which can weigh hundreds of pounds, are typically lifted into the switchgear and racked by mounting the circuit breakers into a drawout cradle. A manually controlled or remotely operated mechanism is inserted into the cradle to turn a crank that racks the circuit breaker into the switchgear and completes an electrical circuit which is protected by the breaker.

p-0004On the backs of these large circuit breakers facing the rear interior of the switchgear cabinet are connection members, such as bus bars, with pivots (also known as “cluster supports”) that jut out like rails on a train track. Onto these pivots are installed multiple “clusters,” which are electrical connectors that have opposing stacks of plate-like fingers. These fingers straddle the pivots and allow the clusters to adapt their positions to engage bus bar connectors, such as fixed stab terminals (“stabs”) or turnable joint mount (TJM) connectors, which are housed inside the switchgear cabinets during the blind rack-in connection. These fingers are biased by spring elements to stay on the pivots so that the cluster “snaps” onto the pivot. It is important that these clusters remain secured on the pivots because if they become loose or dislodged as the circuit breaker is being racked into the switchgear or during operation of the switchgear, a cross-phase connection or a short circuit from an electrical phase to ground can occur.

p-0005The switchgear assembly typically comprises a cabinet that houses a drawout circuit breaker cradle for receiving and supporting the circuit breaker. The drawout cradle simplifies mounting and dismounting of the circuit breaker from field serviceable connections, allowing for ease of installation, removal, and maintenance. At the distal end of the cabinet is a breaker backmold, which is often made from a rigid thermoset material, such as a phenolic resin, and used as a mounting interface. For instance, the backmold attaches to the circuit breaker cradle and provides a mounting surface for current transformers, metering transformers, and the power connectors (e.g., stabs or TJMs). The power connectors are typically designed to engage the circuit breaker clusters, field serviceable connections, and current and metering transformers.

p-0006Contemporary TJM power connectors are solid metallic structures with a rectangular base attached via an intermediate yoke to a two-prong forked head, all of which are integrally formed from hot-extrusion metal-working processes. The yoke, which connects the base to the head of the connector, has a solid square-shaped cross-section and operates to carry electrical current from the bus bar to one or more breaker clusters. Current TJM connectors are not designed to provide optimal current density distribution (e.g., electric current per unit area of cross section) when in operation. Current TJM connector designs also fail to mitigate the proximity effect caused by adjacent current-carrying structures. Moreover, existing TJM connectors are not designed to reduce skin effect or maximize thermal convective cooling.

SUMMARY

p-0007Through the use of multi-physics-based analytical tools, aspects of this disclosure are directed to power connector designs that take into consideration the proximity effect, the skin effect, the current density distribution, and thermal convection theories. This analytical approach, combined with improved metal casting processes, allows for the realization of connector geometries that are better optimized in terms of heat generation, e.g., via joule heating, heat dissipation, e.g., via conduction, convection, and radiation, mechanical strength, material, and weight. The various designs disclosed herein are applicable, in some embodiments, to turnable joint mount (TJM) connectors.

p-0008An advantage of embodiments of the present disclosure includes a reduced amount of material required to make each bus connector, without reducing the current carrying capacity or structural integrity of the bus connector. A significant reduction in material, as well as increased convective heat transfer and reduced proximity effect and skin effect, is realized by optimizing the cross-sectional geometry of the yoke and, in some embodiments, by removing material from the center of the yoke. These advantages are obtained while maintaining the structural integrity of the connector, including the robustness needed to withstand the forces that are present during product installation and a high current electrical interruption.

p-0009According to some aspects of the present disclosure, a power connector is presented for connecting a circuit breaker to an electrically conductive bus bar. The power connector includes a fork-shaped head that is configured to electrically connect to the circuit breaker, and a base that is configured to electrically connect to the bus bar. A yoke extends between and electrically connects the base to the fork-shaped head. The yoke has a transverse cross-section with a length that is greater than a width. The length or width, or both, vary between respective ends of the transverse cross-section.

p-0010According to other aspects of the present disclosure, a power connector is presented for electrically coupling a circuit breaker to an electrically conductive power bus bar of a switchgear assembly. In a non-limiting example, the power connector can be of the TJM connector type. This power connector includes a fork-shaped head with two or more prongs, each of which is configured to receive thereon and electrically connect to one or more breaker clusters protruding from the circuit breaker. The power connector also includes a base that is configured to mount to the switchgear assembly and electrically connect to the bus bar. A yoke extends between and is integrally formed with the base and the fork-shaped head. The yoke has a transverse cross-section with an elongated geometry—i.e., its length is greater than its width. The cross-section is transverse in that it is substantially perpendicular to a centrally located major axis of the power connector. The length and width decrease from the center towards respective ends of the transverse cross-section.

p-0011According to additional aspects of the present disclosure, a switchgear assembly is featured for electrically coupling a circuit breaker to an electrically conductive power bus bar. The switch gear assembly includes a housing, a backmold, and an electrical connector. The housing is designed to receive therein the circuit breaker. The backmold is operatively attached at a distal end of the housing. The electrical connector includes a metallic monolithic body with a fork-shaped head, a base and a yoke. The fork-shaped head electrically connects to the circuit breaker. The base mounts to the backmold and electrically connects to the bus bar. The yoke, which extends between the base and the fork-shaped head, has a transverse cross-section with a length and a width. The transverse cross-section is substantially perpendicular to a major axis of the electrical connector. The length and the width of the cross-section vary between respective ends of the transverse cross-section.

p-0012The foregoing summary is not intended to represent each embodiment or every aspect of the present disclosure. Rather, the foregoing summary merely provides an exemplification of some of the novel features and aspects included herein. The above features and advantages, and other features and advantages of the present disclosure, will be readily apparent from the following detailed description of the embodiments and best modes for carrying out the present invention when taken in connection with the accompanying drawings and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

p-0013<figref idrefs="DRAWINGS">FIG. 1</figref> is a perspective-view illustration of a representative circuit breaker assembly electrically coupled to a representative switchgear assembly in accordance with aspects of the present disclosure.

p-0014<figref idrefs="DRAWINGS">FIG. 2A</figref> is a perspective-view illustration of an exemplary cruciform power connector in accordance with aspects of the present disclosure.

p-0015<figref idrefs="DRAWINGS">FIG. 2B</figref> is an alternative perspective-view illustration of the exemplary power connector of <figref idrefs="DRAWINGS">FIG. 2A</figref>.

p-0016<figref idrefs="DRAWINGS">FIG. 2C</figref> is a plan-view illustration of the exemplary power connector of <figref idrefs="DRAWINGS">FIG. 2A</figref>.

p-0017<figref idrefs="DRAWINGS">FIG. 2D</figref> is an end-view illustration of the exemplary power connector of <figref idrefs="DRAWINGS">FIG. 2A</figref>, which is taken in partial cross-section along line A-A of <figref idrefs="DRAWINGS">FIG. 2C</figref>.

p-0018<figref idrefs="DRAWINGS">FIG. 3A</figref> is a perspective-view illustration of another exemplary cruciform power connector in accordance with aspects of the present disclosure.

p-0019<figref idrefs="DRAWINGS">FIG. 3B</figref> is an alternative perspective-view illustration of the exemplary power connector of <figref idrefs="DRAWINGS">FIG. 3A</figref>.

p-0020<figref idrefs="DRAWINGS">FIG. 4A</figref> is a perspective-view illustration of yet another exemplary cruciform power connector in accordance with aspects of the present disclosure.

p-0021<figref idrefs="DRAWINGS">FIG. 4B</figref> is an alternative perspective-view illustration of the exemplary power connector of <figref idrefs="DRAWINGS">FIG. 4A</figref>.

p-0022<figref idrefs="DRAWINGS">FIG. 5A</figref> is a perspective-view illustration of an exemplary hexagonal power connector in accordance with aspects of the present disclosure.

p-0023<figref idrefs="DRAWINGS">FIG. 5B</figref> is an alternative perspective-view illustration of the exemplary power connector of <figref idrefs="DRAWINGS">FIG. 5A</figref>.

p-0024<figref idrefs="DRAWINGS">FIG. 5C</figref> is a plan-view illustration of the exemplary power connector of <figref idrefs="DRAWINGS">FIG. 5A</figref>.

p-0025<figref idrefs="DRAWINGS">FIG. 5D</figref> is an end-view illustration of the exemplary power connector of <figref idrefs="DRAWINGS">FIG. 5A</figref>, which is taken in partial cross-section along line B-B of <figref idrefs="DRAWINGS">FIG. 5C</figref>.

p-0026<figref idrefs="DRAWINGS">FIG. 6A</figref> is a perspective-view illustration of another exemplary hexagonal power connector in accordance with aspects of the present disclosure.

p-0027<figref idrefs="DRAWINGS">FIG. 6B</figref> is an alternative perspective-view illustration of the exemplary power connector of <figref idrefs="DRAWINGS">FIG. 6A</figref>.

p-0028<figref idrefs="DRAWINGS">FIG. 7A</figref> is a perspective-view illustration of an exemplary vented-diamond power connector in accordance with aspects of the present disclosure.

p-0029<figref idrefs="DRAWINGS">FIG. 7B</figref> is an alternative perspective-view illustration of the exemplary power connector of <figref idrefs="DRAWINGS">FIG. 7A</figref>.

p-0030<figref idrefs="DRAWINGS">FIG. 7C</figref> is a plan-view illustration of the exemplary power connector of <figref idrefs="DRAWINGS">FIG. 7A</figref>.

p-0031<figref idrefs="DRAWINGS">FIG. 7D</figref> is an end-view illustration of the exemplary power connector of <figref idrefs="DRAWINGS">FIG. 7A</figref>, which is taken in partial cross-section along line C-C of <figref idrefs="DRAWINGS">FIG. 7C</figref>.

p-0032<figref idrefs="DRAWINGS">FIG. 8A</figref> is a perspective-view illustration of another exemplary vented-diamond power connector in accordance with aspects of the present disclosure.

p-0033<figref idrefs="DRAWINGS">FIG. 8B</figref> is an alternative perspective-view illustration of the exemplary power connector of <figref idrefs="DRAWINGS">FIG. 8A</figref>.

p-0034While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

p-0035Referring now to the drawings, wherein like reference numbers refer to like components throughout the several views, <figref idrefs="DRAWINGS">FIG. 1</figref> is a perspective-view illustration of a representative circuit breaker assembly, illustrated schematically at <b>10</b>. The circuit breaker assembly <b>10</b> may be of the “draw-out type” circuit breaker. In some non-limiting examples, a suitable circuit breaker assembly <b>10</b> can be based on the exemplary draw-out type circuit breakers disclosed, for example, in U.S. Pat. No. 5,036,427, to Thomas J. Krom et al., or U.S. Pat. No. 4,531,174, to Bernard C. Rickmann. In this regard, the circuit breaker assembly <b>10</b> can be conventionally mounted for movement into and out of a representative switchgear assembly, which is designated generally at <b>12</b> in <figref idrefs="DRAWINGS">FIG. 1</figref>, for connection to an electrically conductive power bus bar. A representative racking device for racking draw-out type circuit breakers into a switchgear cell is disclosed, for example, in U.S. Pat. No. 5,477,017, to David L. Swindler et al. The switchgear assembly <b>12</b> can comprise a convention cabinet (also referred to herein as “enclosure” or “housing”), which is generally represented in the drawings by a rigid backmold (illustrated schematically at <b>30</b>) and a turnable joint coupling (illustrated schematically at <b>32</b>), which can be electrically connected to a power bus bar (not visible in the view provided). Additional information regarding switchgear assemblies can be found in U.S. Pat. No. 6,242,702, to Jacob B. Spiegel et al. While the illustrated embodiment is shown as a switchboard apparatus, it should be understood that the aspects of the present disclosure could be embodied in other types of electrical apparatuses including, without limitation, motor controllers and other load controllers.

p-0036In the illustrated embodiment, the circuit breaker assembly <b>10</b> is electrically coupled to the switchgear assembly <b>12</b> via one or more electrically conductive power connectors <b>14</b>, which can be of the turnable joint mount (TJM) connector type, as explained in further detail below. Although only one power connector <b>14</b> is shown in <figref idrefs="DRAWINGS">FIG. 1</figref>, it should be readily understood that the switchgear assembly <b>12</b> will typically include a number of similarly oriented power connectors <b>14</b>. When properly connected, the breaker <b>10</b> can be operable to distribute power from a primary power source, such as a standard utility power source, to a load. The circuit breaker assembly <b>10</b> includes, for example, a housing <b>18</b> with a rearward facing wall <b>19</b>. Three substantially identical cluster supports <b>20</b>A-C are fixed to the rearward facing wall <b>19</b> of the circuit breaker housing <b>18</b>. Integrally formed with each cluster support <b>20</b>A-C exemplified in <figref idrefs="DRAWINGS">FIG. 1</figref> is a pair of laterally spaced, spade-shaped pivots <b>22</b>A-F. The pivots <b>22</b>A-F are vertically elongated rails that project generally orthogonally from the rearward facing wall <b>19</b> of the circuit breaker housing <b>18</b>. It should be understood that the drawings are not necessarily to scale and are provided purely for descriptive purposes; thus, the individual and relative dimensions and orientations presented herein are not to be considered limiting. To that end, the circuit breaker <b>10</b> can include greater or fewer than three cluster supports <b>20</b>A-C of similar or differing structure to that shown in the drawings.

p-0037In <figref idrefs="DRAWINGS">FIG. 1</figref>, the circuit breaker <b>10</b> is electrically coupled to each power connector <b>14</b> by one or more columns <b>16</b>A-F (two in <figref idrefs="DRAWINGS">FIG. 1</figref>) of self-locking “cluster-type” breaker connectors <b>24</b>A-C. Each column <b>16</b>A-F includes three substantially identical breaker clusters <b>24</b>A-C (i.e., <b>18</b> total breaker connectors in the illustrated embodiment) that are vertically stacked one on top of the other. Each breaker cluster <b>24</b>A-C has a first (“breaker-side”) end portion, designated generally as <b>26</b> in <figref idrefs="DRAWINGS">FIG. 1</figref>, opposing a second (“bus-side”) end portion, designated generally as <b>28</b>. The first end portions <b>26</b> are designed to attach to (e.g., seat on and straddle) one of the spade-shaped pivots <b>22</b>A-F of the cluster supports <b>20</b>A-C. The second end portions <b>28</b>, in contrast, are designed to electrically mate with (e.g., interference-fit and clamp onto an arm <b>15</b>) one of the power connectors <b>14</b>. Each breaker cluster <b>24</b>A-C includes a cage <b>36</b>A-C and a finger cluster <b>34</b>A-C. The finger clusters <b>34</b>A-C generally include a pair of opposing stacks of electrically conductive, elongated plates (also known as “fingers”). The cages <b>36</b>A-C generally act as a functional sleeve or casing, extending generally continuously around the outer perimeter of a respective cluster <b>34</b>A-C to thereby operatively maintain the fingers in their stacks. Although shown interfacing with six breaker clusters <b>24</b>A-C, the power connector <b>14</b> can be configured to mate with fewer or greater than six breaker clusters <b>24</b>A-C, each of which may be similar or different in design to the breaker clusters shown in the drawings. For example, the power connector <b>14</b> can be configured to mate with one or more of the breaker cluster designs presented in commonly owned, copending U.S. patent application Ser. No. 13/013,275, to Timothy R. Faber et al., which was filed on Jan. 25, 2011.

p-0038<figref idrefs="DRAWINGS">FIGS. 2A-2D</figref> illustrate an exemplary power connector, indicated generally at <b>114</b>, in accordance with aspects of the present disclosure. According to this illustrated embodiment, the power connector <b>114</b> comprises three primary segments: a fork-shaped head <b>116</b>, a base <b>118</b>, and a yoke <b>120</b>. In general, the yoke <b>120</b> extends between and electrically connects the base <b>118</b> to the fork-shaped head <b>116</b>. In the illustrated embodiments, for example, the yoke <b>120</b> originates at and projects from the surface of the base <b>118</b> that is opposite the surface which contacts the backmold <b>30</b>; the yoke <b>120</b> terminating at and connecting to the web <b>126</b> of the fork-shaped head <b>116</b>. The head <b>116</b>, the base <b>118</b>, and the yoke <b>120</b> can be integrally formed as a single-piece, monolithic structure. In contrast to conventional practices, it is preferred in some aspects of this disclosure that the power connector <b>114</b> be formed via casting or molding. In so doing, the power connectors disclosed herein can take on additional features and complex 3-dimensional designs that would otherwise be impractical or even impossible through traditional extrusion processes used for fabricating prior art power connectors. It is desirable, in some embodiments, that the power connector <b>114</b> be fabricated from a highly electrically conductive material, such as copper or aluminum.

p-0039The fork-shaped head <b>116</b> is, generally speaking, configured to electrically connect the power connector <b>114</b> to an electrical component, such as the circuit breaker assembly <b>10</b> of <figref idrefs="DRAWINGS">FIG. 1</figref>. The fork-shaped head <b>116</b> illustrated in <figref idrefs="DRAWINGS">FIGS. 2A-2C</figref>, for example, comprises two generally flat, blunt-ended prongs (also known as “tines” or “arms”) <b>122</b> and <b>124</b> that are connected via an intermediate web <b>126</b>. The interconnected prongs <b>122</b>, <b>124</b> and web <b>126</b> collectively define a generally symmetrical U-shaped plan-profile, as best seen in <figref idrefs="DRAWINGS">FIG. 2C</figref>. The first and second prongs <b>122</b>, <b>124</b> have first and second thicknesses T<b>1</b> and T<b>2</b>, respectively, while the web <b>126</b> has a third thickness T<b>3</b>. According to some aspects of the present disclosure, the web <b>126</b> and two prongs <b>122</b>, <b>124</b> have a generally uniform thickness—i.e., the first, second and third thicknesses T<b>1</b>-T<b>3</b> are approximately equal to one another.

p-0040Each prong <b>122</b>, <b>124</b> can be designed to receive thereon and thereby operatively connect to one or more breaker clusters, such as the cluster-type breaker connectors <b>24</b>A-C of <figref idrefs="DRAWINGS">FIG. 1</figref>. By way of non-limiting example, when the circuit breaker assembly <b>10</b> is fed into the switchgear assembly <b>12</b>, for example, via a draw-out rack, the fingers <b>34</b>A-C of one or more breaker clusters <b>24</b>A-C press onto and straddle a respective prong <b>122</b>, <b>124</b>. In this manner, an interference-fit is created between the cluster <b>24</b>A-C and the fork-shaped head <b>116</b> of the power connector <b>114</b>. This allows for electrical current to pass between the circuit breaker <b>10</b> and the power connector <b>114</b> through the breaker clusters <b>24</b>A-C. It should be recognized that the size and shape of the head <b>116</b> generally, or each prong <b>122</b>, <b>124</b> specifically, can be varied, for example, depending upon the intended application of the power connector <b>114</b>.

p-0041The base <b>118</b>, generally speaking, is configured to mount the power connector <b>114</b> to a mounting surface, such as a complementary segment of the switchgear assembly <b>12</b> of <figref idrefs="DRAWINGS">FIG. 1</figref>, and operatively couple the power connector <b>114</b> to an electrical circuit, which may be to a bus bar by way of the turnable joint coupling <b>32</b> of <figref idrefs="DRAWINGS">FIG. 1</figref>. In the illustrated embodiment, for example, the base <b>118</b> is generally symmetrical and tiered, with a contoured platform <b>128</b> that projects generally orthogonally from a generally rectangular stratum <b>130</b>, as best seen in <figref idrefs="DRAWINGS">FIG. 2B</figref>. In some embodiments, the base <b>118</b> can be said to have a “split base” configuration with a keyed (or non-regular) raised platform <b>128</b>. It should be recognized that the size and shape of the base <b>118</b> can be varied from what is shown in the drawings without departing from the scope and spirit of the present disclosure. The platform <b>128</b> has a first mounting surface <b>129</b> that is generally parallel to and spaced (e.g., longitudinally offset) from a second mounting surface <b>131</b> of the stratum <b>130</b>. The first mounting surface <b>129</b> is configured, e.g., via first mounting holes <b>132</b> (<figref idrefs="DRAWINGS">FIG. 2D</figref>), to operatively couple to a bus bar, for example, via turnable joint coupling <b>32</b> of <figref idrefs="DRAWINGS">FIG. 1</figref>. In comparison, the second mounting surface <b>131</b> is configured, e.g., via second mounting holes <b>134</b> (<figref idrefs="DRAWINGS">FIG. 2D</figref>), to attach to a mounting surface, such as the backmold <b>30</b> of switchgear assembly <b>12</b>.

p-0042The yoke <b>120</b>, in general, electrically and mechanically couples the head <b>116</b> to the base <b>118</b>. <figref idrefs="DRAWINGS">FIG. 2D</figref> shows that the yoke <b>120</b> has an transverse cross-section, designated generally at <b>136</b>, with an elongated geometry, i.e., having a length L<b>1</b> that is greater than a width W<b>1</b>. By way of clarification, and not limitation, the cross-section <b>136</b> is a transverse cross-section in that it is generally perpendicular to the longitudinal center axis of the power connector <b>114</b>, which is represented by the center of the crosshair provided in <figref idrefs="DRAWINGS">FIG. 2D</figref>. The transverse cross-section <b>136</b> of <figref idrefs="DRAWINGS">FIGS. 2A-2D</figref> has a cruciform shape comprising two laterally extending ribs <b>142</b> and <b>144</b>, each of which projects generally perpendicularly from a respective opposing side of a column <b>146</b>. The longitudinal center axis can be the major axis (i.e., the axis with the greatest distance between antipodal points) of the power connector <b>114</b>. An optional borehole <b>140</b> extends longitudinally through the power connector <b>114</b> from the base <b>116</b>, through the yoke <b>120</b>, and out the fork-shaped head <b>118</b>. Unlike some conventional connectors, the yoke <b>120</b> of the power connector <b>114</b> can have a complex 3-dimensional geometry. In some embodiments of the present disclosure, for example, the geometric configuration of the yoke <b>120</b> changes in all three planes of a Cartesian coordinate system.

p-0043In contrast to prior designs, the length L<b>1</b> of the transverse cross-section <b>136</b> of the yoke <b>120</b> in <figref idrefs="DRAWINGS">FIGS. 2A-2D</figref> is not constant along its width W<b>1</b>, and the width W<b>1</b> of the transverse cross-section <b>136</b> is not constant along its length L<b>1</b>. For instance, the length designated L<b>1</b>′ is shorter that L<b>1</b> whose arrow points touch the respective ends of that dimension in <figref idrefs="DRAWINGS">FIG. 2D</figref>. Likewise, for example, the width designated W<b>1</b>′ is shorter that the width designated W<b>1</b> whose arrow points touch the respective ends of that dimension in <figref idrefs="DRAWINGS">FIG. 2D</figref>. According to the illustrated embodiment, the length L<b>1</b> decreases, for example, to L<b>1</b>′ as you move from the longitudinally oriented center line C<b>1</b> of <figref idrefs="DRAWINGS">FIG. 2D</figref> toward either respective lateral end (or side) of the transverse cross-section <b>136</b>. In a similar regard, the width W<b>1</b> of the transverse cross-section <b>136</b> decreases, for example, to W<b>1</b>′ as you move from the laterally oriented center line C<b>2</b> of <figref idrefs="DRAWINGS">FIG. 2D</figref> toward either respective longitudinal end (or side) of the transverse cross-section <b>136</b>. Thus, the length L<b>1</b> or the width W<b>1</b>, or both as illustrated herein, are varying between their respective ends of the transverse cross-section. In addition, the outer periphery of the transverse cross-section <b>136</b> of the yoke <b>120</b> includes a plurality of round-chamfered corners <b>138</b> (eight in the illustrated embodiment).

p-0044An advantage of the embodiment presented in <figref idrefs="DRAWINGS">FIGS. 2A-2D</figref> includes a reduced amount of material required to make each power connector <b>114</b>, while maintaining the requisite current carrying capacity (e.g., 1600-2000 A at 60 Hz) and structural integrity (e.g., mechanical and electrical loads of 1500 kg and 320 ka, respectively) for normal operation thereof. This significant reduction in material is realized by optimizing the cross-sectional geometry of the yoke <b>120</b> and via inclusion of the borehole <b>140</b>. These advantages are achieved while maintaining the structural integrity of the power connector <b>114</b>, including the robustness needed to withstand the forces that are present during product installation and a high current electrical interruption.

p-0045Through the use of mathematical modeling and analytical tools, these optimized geometries are designed while taking into consideration the proximity effect, the skin effect, and thermal convection theories. The phenomenon known as “skin effect” holds that the current density near the surface of the conductor is greater than at its core. The skin effect, in other words, is the tendency of an alternating electric current (AC) to distribute itself within a conductor with the current density being largest near the surface of the conductor, decreasing at greater depths. The skin effect causes the effective resistance of the conductor to increase at higher frequencies where the skin depth is smaller, thus reducing the effective cross-section of the conductor. Moreover, in multi-phase systems, adjacent connectors are subjected to another undesirable phenomenon called the “proximity effect,” which relates to how current flowing through one phase affects the current flowing through an adjacent phase. In a conductor carrying alternating current, if currents are flowing through one or more other nearby conductors, such as within adjacent TJM connectors, the distribution of current within the first conductor will be constrained to smaller regions due to alternating magnetic fields in the adjacent conductors. The resulting current crowding is termed the “proximity effect.” The yoke <b>120</b> design presented herein significantly reduces both the skin effect and the proximity effect when compared to its conventional connector counterparts. In some embodiments, the yoke <b>120</b> has a current density when electricity flows therethrough, the current density being more generally uniformly distributed across the transverse cross-section <b>136</b> of the yoke <b>120</b> than what is available in comparable conventional designs.

p-0046Turning next to <figref idrefs="DRAWINGS">FIGS. 3A and 3B</figref>, wherein similar reference numerals refer to similar components from the other drawings, another exemplary power connector, indicated generally at <b>214</b>, is presented in accordance with aspects of the present disclosure. Like the power connector <b>114</b> embodied in <figref idrefs="DRAWINGS">FIGS. 1A-1D</figref>, the power connector <b>214</b> comprises three primary segments: a fork-shaped head <b>216</b>, a base <b>218</b>, and a yoke <b>220</b>. In the embodiment illustrated in <figref idrefs="DRAWINGS">FIGS. 3A and 3B</figref>, the head <b>216</b>, base <b>218</b>, and yoke <b>220</b> are structurally and functionally similar to the head <b>116</b>, base <b>118</b>, and yoke <b>120</b> of <figref idrefs="DRAWINGS">FIGS. 2A-2D</figref>. For instance, the yoke <b>220</b> extends between and electrically and mechanically connects the base <b>218</b> to the fork-shaped head <b>216</b>. In addition, the head <b>216</b> is configured to electrically connect the power connector <b>214</b> to an electrical component, such as the circuit breaker assembly <b>10</b> of <figref idrefs="DRAWINGS">FIG. 1</figref>. As another example of similarity, the base <b>218</b> is configured to mount the power connector <b>214</b> to a mounting surface, such as a complementary segment of the switchgear assembly <b>12</b> of <figref idrefs="DRAWINGS">FIG. 1</figref>, and operatively couple the power connector <b>214</b> to an electrical circuit, which may be by way of a power bus bar. In yet another example, the yoke <b>220</b> has a transverse cross-section with an elongated cruciform shape comprising two mutually perpendicular overlapping rectangular segments. The yoke <b>220</b> can be optimized similar to the yoke <b>120</b> to increase thermal dissipativity, reduce the skin effect, the proximity effect, and connector material, while maintaining the requisite current carrying capacity and structural integrity. Therefore, for efficiency and conciseness, these components will not be described again in detail. A primary difference between the power connector <b>214</b> of <figref idrefs="DRAWINGS">FIGS. 3A and 3B</figref> and the power connector <b>114</b> presented in <figref idrefs="DRAWINGS">FIGS. 2A-2D</figref> is the overall size and weight of the connector <b>214</b>. In particular, the power connector <b>214</b> has a larger height H<b>2</b> than the height H<b>1</b> of the power connector <b>114</b>. As such, the power connector <b>214</b> also has a larger electrical and mechanical load carrying capacity.

p-0047Referring to <figref idrefs="DRAWINGS">FIGS. 4A and 4B</figref>, wherein similar reference numerals refer to similar components from the other Figures, another exemplary power connector, indicated generally at <b>314</b>, is presented in accordance with aspects of the present disclosure. Like the power connectors <b>114</b> and <b>214</b> discussed above, the power connector <b>314</b> comprises three primary segments: a fork-shaped head <b>316</b>, a base <b>318</b>, and a yoke <b>320</b>. In the embodiment illustrated in <figref idrefs="DRAWINGS">FIGS. 4A and 4B</figref>, the head <b>316</b>, base <b>318</b>, and yoke <b>320</b> are structurally and functionally similar to the head <b>116</b>, base <b>118</b>, and yoke <b>120</b> of <figref idrefs="DRAWINGS">FIGS. 2A-2D</figref>. By way of non-limiting example, the yoke <b>320</b> extends between and electrically and mechanically connects the base <b>318</b> to the fork-shaped head <b>316</b>. Additionally, the head <b>316</b> is configured to electrically connect the power connector <b>314</b> to an electrical component, such as the circuit breaker assembly <b>10</b> of <figref idrefs="DRAWINGS">FIG. 1</figref>. As another example of similarity, the base <b>318</b> is configured to mount the power connector <b>314</b> to a mounting surface, such as a complementary segment of the switchgear assembly <b>12</b> of <figref idrefs="DRAWINGS">FIG. 1</figref>, and operatively couple the power connector <b>314</b> to an electrical circuit, which may be by way of a power bus bar. In yet another example, the yoke <b>320</b> has a transverse cross-section with an elongated cruciform shape. The yoke <b>320</b> can be optimized similar to the yoke <b>120</b> to increase thermal dissipativity, reduce the skin effect, the proximity effect, and connector material, while maintaining the requisite current carrying capacity and structural integrity. Consequently, for brevity and conciseness, these components will not be described again in detail.

p-0048One difference between the power connector <b>314</b> of <figref idrefs="DRAWINGS">FIGS. 4A and 4B</figref> and the power connectors <b>114</b> and <b>214</b> is the overall size and weight of the connector <b>214</b>. In particular, the power connector <b>214</b> has a larger height H<b>3</b> than the height H<b>1</b> of the power connector <b>114</b> and the height H<b>2</b> of the power connector <b>214</b>. In some embodiments, the height H<b>1</b> is approximately 2 inches (5.1 cm), the height H<b>2</b> is approximately 3 in (7.6 cm), whereas the height H<b>3</b> is 5 in (12.7 cm). As such, the power connector <b>314</b> also has a larger electrical and mechanical load carrying capacity than the power connectors <b>114</b> and <b>214</b>. In addition, the cruciform transverse cross-section of the yoke <b>320</b> comprises four laterally extending ribs, two of which are visible in the views provided (designated <b>342</b> and <b>344</b> in <figref idrefs="DRAWINGS">FIG. 4A</figref>). The first pair of the ribs <b>342</b>, <b>344</b> project generally perpendicularly from a first side of a column <b>346</b>, while the second pair (not visible) project generally perpendicularly from a second side of the column <b>346</b>, which opposes the first side. In addition, the power connector <b>314</b> includes a first circular borehole <b>340</b> that is vertically spaced from a second circular borehole <b>348</b>, both of which extend longitudinally through the power connector <b>314</b> from the base <b>316</b>, through the yoke <b>320</b>, and out the fork-shaped head <b>318</b>.

p-0049<figref idrefs="DRAWINGS">FIGS. 5A-5D</figref> illustrate a different exemplary power connector, indicated generally at <b>414</b>, in accordance with aspects of the present disclosure. Similar to the power connectors <b>114</b>, <b>214</b> and <b>314</b>, the power connector <b>414</b> comprises three primary segments: a fork-shaped head <b>416</b>, a base <b>418</b>, and a yoke <b>420</b>. In the illustrated embodiments, the yoke <b>420</b> originates at and projects from the surface of the base <b>418</b> that is opposite the surface which contacts the backmold <b>30</b>; the yoke <b>420</b> terminating at and connecting to the web of the fork-shaped head <b>416</b>. The head <b>416</b> and the base <b>418</b> of the embodiment presented in <figref idrefs="DRAWINGS">FIGS. 5A-5D</figref> are structurally and functionally similar to the head <b>116</b> and base <b>118</b> of <figref idrefs="DRAWINGS">FIGS. 2A-2D</figref>. To that end, unless explicitly indicated otherwise, the power connector <b>414</b> can include any of the features and options discussed above or below. Consequently, only key points of possible distinction are developed in further detail below.

p-0050<figref idrefs="DRAWINGS">FIG. 5D</figref> shows that the yoke <b>420</b> has a transverse cross-section, designated generally at <b>436</b>, with an elongated hexagonal shape comprising six substantially flat sides. The transverse cross-section <b>436</b> is generally perpendicular to the longitudinal center axis of the power connector <b>414</b>, which is represented by the center of the crosshair provided in <figref idrefs="DRAWINGS">FIG. 5D</figref>. An optional oblong-shaped borehole <b>440</b> extends longitudinally through the power connector <b>414</b> from the base <b>418</b>, through the yoke <b>420</b>, and out the fork-shaped head <b>416</b>. Unlike some conventional connectors, the yoke <b>420</b> of the power connector <b>414</b> can have a complex 3-dimensional geometry. In some embodiments of the present disclosure, for example, the geometric configuration of the yoke <b>420</b> changes in all three planes of a Cartesian coordinate system.

p-0051In contrast to prior designs, the length L<b>2</b> of the transverse cross-section <b>436</b> of the yoke <b>420</b> in <figref idrefs="DRAWINGS">FIGS. 5A-5D</figref> is not constant along its width W<b>2</b>, and the width W<b>2</b> of the transverse cross-section <b>436</b> is not constant along its length L<b>2</b>. According to the illustrated embodiment, the length L<b>2</b> decreases, for example, to L<b>2</b>′ as you move from the longitudinally oriented center line C<b>3</b> of <figref idrefs="DRAWINGS">FIG. 5D</figref> toward either respective lateral end (or side) of the transverse cross-section <b>436</b>. In a similar regard, the width W<b>2</b> of the transverse cross-section <b>436</b> decreases, for example, to W<b>2</b>′ as you move from the laterally oriented center line C<b>4</b> of <figref idrefs="DRAWINGS">FIG. 5D</figref> toward either longitudinal end (or side) of the transverse cross-section <b>436</b>. Thus, the length L<b>2</b> or the width W<b>2</b>, or both as illustrated herein, are varying between their respective ends of the transverse cross-section.

p-0052As seen in the cross-section illustration presented in <figref idrefs="DRAWINGS">FIG. 5D</figref>, the outer periphery of the transverse cross-section <b>436</b> has a plurality of sides <b>442</b>-<b>445</b>, each of which tapers as you move from either center line C<b>3</b>, C<b>4</b> towards the respective ends of the transverse cross-section <b>436</b>. In addition, the outer periphery of the transverse cross-section <b>436</b> of the yoke <b>420</b> includes a plurality of round-chamfered corners <b>438</b> (six in the illustrated embodiment). Analogous to the embodiments presented in the other Figures, the yoke <b>420</b> of <figref idrefs="DRAWINGS">FIGS. 5A-5D</figref> is optimized to increase thermal dissipativity, reduce the skin effect, the proximity effect, and connector material, while maintaining the requisite current carrying capacity and structural integrity.

p-0053Referring to <figref idrefs="DRAWINGS">FIGS. 6A and 6B</figref>, wherein similar reference numerals refer to similar components from the other Figures, another exemplary power connector, indicated generally at <b>514</b>, is presented in accordance with aspects of the present disclosure. Similar to the various power connector embodiments discussed above, the power connector <b>514</b> comprises three primary segments: a fork-shaped head <b>516</b>, a base <b>518</b>, and a yoke <b>520</b>. In the embodiment illustrated in <figref idrefs="DRAWINGS">FIGS. 6A and 6B</figref>, the head <b>516</b>, base <b>518</b>, and yoke <b>520</b> are structurally and functionally similar to the head <b>416</b>, base <b>418</b>, and yoke <b>420</b> of <figref idrefs="DRAWINGS">FIGS. 5A-5D</figref>. By way of non-limiting example, the yoke <b>520</b> extends between and electrically and mechanically connects the base <b>518</b> to the head <b>516</b>. Additionally, the fork-shaped head <b>516</b> is configured to electrically connect the power connector <b>514</b> to an electrical component, such as the circuit breaker assembly <b>10</b> of <figref idrefs="DRAWINGS">FIG. 1</figref>. As another example of similarity, the base <b>518</b> is configured to mount the power connector <b>514</b> to a mounting surface, such as a complementary segment of the switchgear assembly <b>12</b> of <figref idrefs="DRAWINGS">FIG. 1</figref>, and operatively couple the power connector <b>514</b> to an electrical circuit, which may be by way of a power bus bar. In yet another example, the yoke <b>520</b> has a transverse cross-section with an elongated hexagonal shape comprising six substantially flat sides. The yoke <b>520</b> can be configured and otherwise optimized similar to the yoke <b>420</b> to increase thermal dissipativity, reduce the skin effect, the proximity effect, and connector material, while maintaining the requisite current carrying capacity and structural integrity. Consequently, for brevity and conciseness, these components will not be described again in detail.

p-0054A primary difference between the power connector <b>514</b> of <figref idrefs="DRAWINGS">FIGS. 6A and 6B</figref> and the power connector <b>414</b> is the overall size and weight of the connector <b>514</b>. In particular, the power connector <b>514</b> has a larger height H<b>5</b> than the height H<b>4</b> of the power connector <b>414</b>. In some embodiments, the height H<b>4</b> is approximately 2 inches (5.1 cm), whereas the height H<b>5</b> is approximately 3 in (7.6 cm). As such, the power connector <b>514</b> also has a larger electrical and mechanical load carrying capacity than the power connector <b>414</b>.

p-0055Turning then to <figref idrefs="DRAWINGS">FIGS. 7A-7D</figref>, an additional exemplary power connector, indicated generally at <b>614</b>, in presented accordance with additional aspects of the present disclosure. Similar to aforementioned power connectors <b>114</b>, <b>214</b>, <b>314</b>, <b>414</b> and <b>514</b>, the power connector <b>614</b> comprises three primary segments: a fork-shaped head <b>616</b>, a base <b>618</b>, and a yoke <b>620</b>. In the illustrated embodiments, the yoke <b>620</b> originates at and projects from the surface of the base <b>618</b> that is opposite the surface which contacts the backmold <b>30</b>; the yoke <b>620</b> terminating at and connecting to the web of the fork-shaped head <b>616</b>. The head <b>616</b> and the base <b>618</b> of the embodiment presented in <figref idrefs="DRAWINGS">FIGS. 7A-7D</figref> are structurally and functionally similar to the head <b>116</b> and base <b>118</b> of <figref idrefs="DRAWINGS">FIGS. 2A-2D</figref>. To that end, unless explicitly indicated otherwise, the power connector <b>614</b> can include any of the features and options discussed above or below. Consequently, only key points of distinction are described in detail hereinbelow.

p-0056The yoke <b>620</b> of the power connector <b>614</b> is shown in <figref idrefs="DRAWINGS">FIG. 7D</figref> with a transverse cross-section, designated generally at <b>636</b>, with a diamond (also referred to herein as “vented-diamond”) shape. The transverse cross-section <b>636</b> is generally perpendicular to the longitudinal center axis of the power connector <b>614</b>, which is represented by the center of the crosshair provided in <figref idrefs="DRAWINGS">FIG. 6D</figref>. In contrast to the embodiments discussed above and below, the major axis of the elongated transverse cross-section <b>636</b> (i.e., the axis with the greatest distance between antipodal points) is generally parallel to the major axis of the base <b>618</b>. Another point of distinction is that the elongated transverse cross-section of the yoke <b>618</b> comprises three distinct cross-sectional areas <b>642</b>-<b>644</b>. These distinct cross-sectional areas <b>642</b>-<b>644</b> are created, at least in part, because the yoke <b>620</b> defines one or more, and in some embodiments at least two venting slots <b>646</b> and <b>648</b>, each of which extends transversely through the yoke <b>620</b>. In non-limiting examples, the first and third cross-sectional areas <b>642</b> and <b>644</b> are shown in <figref idrefs="DRAWINGS">FIG. 7D</figref> with a common triangular shape and each positioned on a respective opposing side of the second cross-sectional area <b>643</b>, which has a hexagonal shape. These venting slots <b>646</b>, <b>648</b> provide increased convective thermal dissipation over the other embodiments disclosed herein, without compromising structural integrity.

p-0057In contrast to prior designs, the length L<b>3</b> of the transverse cross-section <b>636</b> of the yoke <b>620</b> in <figref idrefs="DRAWINGS">FIGS. 7A-7D</figref> is not constant along its width W<b>3</b>, and the width W<b>3</b> of the transverse cross-section <b>636</b> is not constant along its length L<b>3</b>. According to the illustrated embodiment, the length L<b>3</b> decreases, for example, to L<b>3</b>′ as you move from the longitudinally oriented center line C<b>5</b> of <figref idrefs="DRAWINGS">FIG. 7D</figref> toward either lateral end (or side) of the transverse cross-section <b>636</b>. In a similar regard, the width W<b>3</b> of the transverse cross-section <b>636</b> decreases, for example, to W<b>3</b>′ as you move from the laterally oriented center line C<b>6</b> of <figref idrefs="DRAWINGS">FIG. 7D</figref> toward either longitudinal end (or side) of the transverse cross-section <b>636</b>. Thus, the length L<b>3</b> or the width W<b>3</b>, or both as illustrated herein, are varying between their respective ends of the transverse cross-section.

p-0058An optional oblong-shaped borehole <b>640</b> extends longitudinally through the power connector <b>614</b> from the base <b>618</b>, through the yoke <b>620</b>, and out the fork-shaped head <b>616</b>. Unlike some conventional connectors, the yoke <b>620</b> of the power connector <b>614</b> can have a complex <b>3</b>-dimensional geometry. In some embodiments of the present disclosure, for example, the geometric configuration of the yoke <b>620</b> changes in all three planes of a Cartesian coordinate system. Analogous to the embodiments presented in the other Figures, the yoke <b>620</b> of <figref idrefs="DRAWINGS">FIGS. 7A-7D</figref> is optimized to increase thermal dissipativity, reduce the skin effect, the proximity effect, and connector material, while maintaining the requisite current carrying capacity and structural integrity.

p-0059Referring to <figref idrefs="DRAWINGS">FIGS. 8A and 8B</figref>, wherein similar reference numerals refer to similar components from the other Figures, another exemplary power connector, indicated generally at <b>714</b>, is presented in accordance with aspects of the present disclosure. Similar to the various power connector embodiments discussed above, the power connector <b>714</b> comprises three primary segments: a fork-shaped head <b>716</b>, a base <b>718</b>, and a yoke <b>720</b>. In the embodiment illustrated in <figref idrefs="DRAWINGS">FIGS. 8A and 8B</figref>, the head <b>716</b>, base <b>718</b>, and yoke <b>720</b> are structurally and functionally similar to the head <b>616</b>, base <b>618</b>, and yoke <b>620</b> of <figref idrefs="DRAWINGS">FIGS. 7A-7D</figref>. By way of non-limiting example, the yoke <b>720</b> extends between and electrically and mechanically connects the base <b>718</b> to the head <b>716</b>. Additionally, the fork-shaped head <b>716</b> is configured to electrically connect the power connector <b>714</b> to an electrical component, such as the circuit breaker assembly <b>10</b> of <figref idrefs="DRAWINGS">FIG. 1</figref>. As another example of similarity, the base <b>718</b> is configured to mount the power connector <b>714</b> to a mounting surface, such as a complementary segment of the switchgear assembly <b>12</b> of <figref idrefs="DRAWINGS">FIG. 1</figref>, and operatively couple the power connector <b>714</b> to an electrical circuit, which may be by way of a power bus bar. In yet another example, the yoke <b>720</b> has an elongated transverse cross-section, which has a diamond or “vented-diamond” shape comprising four substantially flat peripheral sides and a pair of generally parallel venting slots (only one of which is partially visible in the drawings and designated <b>746</b> in <figref idrefs="DRAWINGS">FIG. 8B</figref>). The yoke <b>720</b> can be configured and otherwise optimized similar to the yoke <b>620</b> to increase thermal dissipativity, reduce the skin effect, the proximity effect, and connector material, while maintaining the requisite current carrying capacity and structural integrity. Consequently, for brevity and conciseness, these components will not be described again in detail.

p-0060A primary difference between the power connector <b>714</b> of <figref idrefs="DRAWINGS">FIGS. 8A and 8B</figref> and the power connector <b>614</b> is the overall size and weight of the power connector <b>714</b>. In particular, the power connector <b>714</b> has a larger height H<b>7</b> than the height H<b>6</b> of the power connector <b>614</b>. In some embodiments, the height H<b>7</b> is approximately 2 inches (5.1 cm), whereas the height H<b>6</b> is approximately 3 in (7.6 cm). As such, the power connector <b>714</b> also has a larger electrical and mechanical load carrying capacity than the power connector <b>614</b>.

p-0061While particular aspects, embodiments, and applications of the present disclosure have been illustrated and described, it is to be understood that the present disclosure is not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations may be apparent from the foregoing descriptions without departing from the spirit and scope of the invention as defined in the appended claims. Lastly, all of the patent and non-patent literature discussed above is incorporated herein by reference.